Devices for operating a spring and pressure controlled preselection diaphragm in photographic lens mounts

ABSTRACT

A photographic lens mount includes a spring and pressure controlled preselection diaphragm which participates in the focusing motion along the optical axis, a Bowden cable, and means for actuating the diaphragm. Part of the actuating means projects from the lens mount into the camera. The Bowden cable connects the actuating means with the diaphragm and controls the diaphragm setting by push and pull.

[ Dec. 25, 1973 United States mm [1 1 Klupsch et a1.

[5 1 DEVICES FOR OPERATING A SPRING AND 3.344.726 10/1967 WellerPRESSURE CONTROLLED PRESELECTION 1 169 464 2/1965 Koppfin DIAPHRAGM INPHOTOGRAPHIC LENS f 'i MOUNTS [76] inventors: Paul Klupscll, 23, AmJohunnisberg;

Primary ExaminerSamuel S. Matthews n 1 s m a d A E mm UH RN kd .IU 88 .mmm xN r m n r mm AA Rudolf Paul, 14, Thomas-Mann-Strasse; UlrichDressler, 6, Geleitsstrasse, all of Jena, Germany ABSTRACT [22] Filed:Mar. 11, 1969 p aOd m w h mm o m fi m m m m om m m d m mTm n H Smomafimnw u ea a o mmwm mh CUmm swmudaegwc ne.l. r. kmww m fim .W-W MWMt.l eam ae mluL l Pw m o nn o m mc m o Sd Sr eW S N l f N CO0 U l d W dA UIF H. T T O O N I 2 Claims, 2 Drawing Figures 2,334,075 11/1943Davenport.............,............ 95/64 A DEVICES FOR OPERATING ASPRING ANI) PRESSURE CONTROLLED PRESELECTION DIAPHRAGM IN PHOTOGRAPHICLENS MOUNTS This invention relates to devices for operating spring andpressure controlled preselection diaphragms in photographic lens mounts.In known devices of that kind, various lever systems operativelyconnected to the shutter release of the camera, influence the setting ofthe diaphragm irrespective of the axial displacement of the diaphragm inthe process of focusing. The same purpose is served by a system oftransmission levers in the mount which are provided with sliding edgesor slide extensions.

Devices of the foregoing kind have the disadvantage that tilting andfriction moments, play in the bearings, complicated mechanical setup,and movement of too great masses go far to imperil the reliability andaccuracy of the lens, particularly if there is considerable axialdisplacement of the diaphragm.

The present invention aims at increasing the working reliability anddecreasing the complexity of spring and pressure controlled preselectiondiaphragms, particularly such diaphragms as are axially displaced duringthe focusing operation, by reducing to a minimum the masses required foroperating the diaphragm and the friction and tilting moments due todiaphragm displacement.

To this end, the present invention consists ofa device for operating aspring and pressure controlled preselection diaphragm in photographiclens mounts, the diaphragm participating in the focusing motion alongthe optical axis, wherein a diaphragm actuating means projecting fromthe mount into the camera is connected with the diaphragm by means of aBowden control cable which responds to tension and pressure regardlessof the diaphragm displacement along the optical axis.

Advantageously, the conduit of the Bowden control cable is a flexibletube which winds around the focusing member at a small distancetherefrom and the two ends ofwhich are respectively secured to the lensmount and the focusing member. Alternatively, the conduit of the Bowdencontrol cable may be a tubular body of C shaped cross-section the openside of which faces, or faces away from, the optical axis.

In order that the invention maybe more readily understood, reference ismade to the accompanying drawing which illustrates the inventiondiagrammatically and by way of example, and in which FIG. 1 is a lensmount including a focusing member, a Bowden control cable and thediaphragm release, and

FIG. 2 is part of a Bowden control cable sheathed in a flexible conduitof approximately semi-circular crosssection.

In the drawing, a lens mount 21 houses a focusing member 1 which issecured against torsion and includes a stationary diaphragm between twolens elements (not shown). The diaphragm comprises leaves 2 (only oneshown), a non-rotatable leaf guide ring 3 and a slotted disc 4 fordiaphragm adjustment. A tension spring 5 tends to rotate the disc 4clockwise (as shown in the drawing), so as to set the diaphragm at itsminimum value. This rotation is however impeded by a stop 6 on 6 thedisc 4 which 18 urged into contact with the one end of a cable 7 of aBowden 8 and, as shown in FIG. 1, keeps the diaphragm at its maximumvalue.

When the shutter of the camera is released, a pin 9 protruding from thepart of the mount next to the camera housing is so disengaged by meansnot shown in the drawing as to be displaced towards the camera in thedirection of the arrow. The motion of the pin 9 is followed by that of alever 10 10 in the form of a T, which is operatively connected with thespring 5 through a plate 11 fast with the lever arm 10 the cable 7 thestop 6 and the disc 4 Accordingly, the disc 4 is displaced in thedirection of the arrow until a lug 12 lies against a variable stop 13set to correspond to the preselected value, to which the diaphragm isthus reduced. When a photograph has been taken, means in the camera (notshown) restore the pin 9 automatically against the direction of thearrow to the position illustrated in the drawing, and the diaphragmreassumes its maximum value.

The lever arms 10 and 10 are so attached to one another by a pin 14 anda tension spring 15 as to be mutually at right angles. Possible toogreat deflection is compensated by the spring 15 an expansion of thisspring causing a respective alteration of the angle between 10 and 10' Atwo-arm lever 17 fulcrums about an axle 16 and protrudes from thefocusing member 1 When switched by hand in the direction of the arrow,the lever 17 acts on the lever 10 10' in such a manner that the Bowdencable 7 sets the diaphragm at the preselected value, the spring 15causing the arm 10' to rotate without the arm 10 which is prevented bythe pin 9 Thus the operator, when pressing against the lever 17, isenabled to view through the camera and objective, and thereby to examinethe depth of field correspond-, ing to the pre-selected diaphragmaperture.

The two ends 8' and 8" of the Bowden 8 are respectively held in bearings18 and 19 the bearing 19 being secured to the mount 21 The Bowdencontrol cable shown in FIG. 2 is sheathed in a flexible conduit 20 ofapproximately semi-circular cross-section. The conduit 20 winds aroundthe focusing member 1 at a small distance therefrom and its ends arerespectively secured to the focusing member 1 and the mount 21 Theflexibility of the conduit 20 enables the focusing member 1 to movewithout hindrance, so that the diaphragm can be operated irrespective offocusing adjustment.

We claim:

1. A device for operating preselector means in the lens mount of aphotographic camera, comprising:

a lens focusing and preselector diaphragm holding means, longitudinallydisplaceable within the lens mount; an actuating means extending intoand from the lens mount at a location spaced from the displaceable lensfocusing and diaphragm holding means; and a Bowden cable for controllingthe aperture of the preselector diaphragm, said cable being entirelydisposed within the lens mount, one end of said cable being attached tothe inner end of said actuating means and the other, to the lensfocusing and diaphragm holding means, so that the other end of saidcable can participate in the displacement of the lens focusing anddiaphragm holding means but the cable cannot be contacted from theoutside of the camera except through said actuating means.

2. A device as described in claim 1 wherein the preselector diaphragm isspring controlled and said cable provides means adapted to release thespring.

1. A device for operating preselector means in the lens mount of aphotographic camera, comprising: a lens focusing and preselectordiaphragm holding means, longitudinally displaceable within the lensmount; an actuating means extending into and from the lens mount at alocation spaced from the displaceable lens focusing and diaphragmholding means; and a Bowden cable for controlling the aperture of thepreselector diaphragm, said cable being entirely disposed within thelens mount, one end of said cable being attached to the inner end ofsaid actuating means and the other, to the lens focusing and diaphragmholding means, so that the other end of said cable can participate inthe displacement of the lens focusing and diaphragm holding means butthe cable cannot be contacted from the outside of the camera exceptthrough said actuating means.
 2. A device as described in claim 1wherein the preselector diaphragm is spring controlled and said cableprovides means adapted to release the spring.